獣医臨床皮膚科 21 (1): 7–9, 2015

Original

An Open Clinical Trial on the Efficacy of Loratadine for the Management of Allergic Pruritus in 27 Cats 27 頭の猫に発症したアレルギー性そう痒を管理するための ロラタジンの有効性に関するオープン臨床試験

Danny W. Scott*, Heather D. Edginton, William H. Miller, Jr., Mitzi D. Clark Department of Clinical Sciences, College of Veterinary Medicine, Cornell University

Received October 16, 2014 and accepted January 7, 2015

Abstract: Anecdotal information in textbook and on the internet indicates that the second generation , loratadine, is useful in the management of cats with allergic dermatitis. Loratadine was administered orally at 5 mg/cat, every 24 hours, to 27 cats with allergic skin disease. Pruritus was satisfactorily controlled in only one cat (4%). No adverse side effects were reported. Key words: allergic dermatitis, cat, loratadine

要 約：第 2 世代の抗ヒスタミン薬であるロラタジンが，猫アレルギー性皮膚炎の管理に有効であ るという逸話的情報が教科書やインターネット上で報告されている。そこでロラタジンをアレル ギー性皮膚炎に罹患した 27 頭の猫に，5 mg/cat で 1 日 1 回経口投与した。その結果，わずか 1 頭（4％） の猫においてそう痒を良好に管理することが可能であった。有害事象は認められなかった。 キーワード：アレルギー性皮膚炎，猫，ロラタジン

(Jpn J Vet Dermatol 2015, 21 (1): 7–9)

7, a) Introduction information suggests that loratadine (5 mg, cat, given orally, every 24 hours) is also useful for the management Allergic skin diseases (atopic dermatitis, food , of cats with allergic dermatitis. flea-bite allergy, -bite allergy) are very common The purpose of this article is to report the results of in cats, accounting for 32.7% of all feline dermatological an open clinical trial on the use of loratadine for the diagnoses in a recent 15-year study10). management of pruritus in allergic cats. are frequently used in the management of feline allergic 6, 7, 11) dermatitis, especially atopic dermatitis . However, Materials and Methods peer-reviewed publications on the use of antihistamines for the management of pruritus in allergic cats are few in Twenty-seven cats (Table 1) with cutaneous number1, 4, 5, 9). reaction patterns typical of allergic skin disease were Loratadine is a second generation (nonsedating) enrolled into the study as they were examined by the tricyclic antihistamine used in humans with allergic Dermatology Service at the Cornell University Hospital rhinitis, conjunctivitis, and dermatitis3). Anecdotal for Animals (CUHA) if their owners agreed to the protocol. The cats included 12 castrated males and 15 * Correspondence to: Danny W. Scott, (Department of Clinical spayed females and ranged in age from 1 to 16 years. Sciences, College of Veterinary Medicine, Cornell University), Ithaca, New York 14853-6401, USA There were 24 domestic shorthair cats, 2 domestic FAX +1-607-253-3534 E-mail: [email protected] longhair cats, and 1 Siamese. They ranged in weight 8 Loratadine in Pruritic Cats

from 3.2 to 5.5 kg. Table 1. Data on 27 cats with allergic dermatitis* treated All cats exhibited one or more of the following with loratadine 6, 11, 12) cutaneous patterns typical of allergic cats : initially Age Duration of Case Breed† Sex‡ lesionless symmetrical pruritus (involving the face, (years) disease (years) pinnae, and/or neck) often leading to excoriation 1 DSH 4 FS 0.5 (cases 1, 5, 7, 8, 10–13, 19–23); self-induced hair loss 2 DLH 3 FS 0.5 (involving the abdomen, back, and/or legs) with normal- 3 DSH 7 MC 0.5 appearing skin (cases 2–6, 13, 14, 17, 19–22, 26, 27); 4 DSH 7 MC 3.0 miliary dermatitis (papulocrustous dermatitis involving 5 DSH 5 MC 1.0 the neck and back) (cases 9, 12, 13, 17, 23); and 6 DSH 8 MC 0.5 eosinophilic complex (eosinophilic plaques 7 DSH 2 MC 1.5 and of ventral abdomen, caudal thighs, and 8 DSH 4 MC 0.5 upper lips) (cases 15, 16, 18). The duration of clinical 9 DSH 6 MC 2.0 signs varied from 2 months to 3 years. The clinical 10 DSH 3 FS 1.0 signs in all cats had regressed completely with systemic 11 DSH 4 MC 1.5 12 DSH 16 FS 2.0 treatment: methylprednisolone acetate, 13 DSH 5 FS 1.0 20 mg/cat, subcutaneously (cases 1,2,9,11–13, 16, 19, 14 DSH 3 FS 0.5 22, 23, 26); prednisolone, 2.2 mg/kg, given orally every 15 Siamese 10 MC 1.0 24 hours (cases 1, 3, 4, 6 10, 15, 17, 20–22, 24, 25, 27); 16 DSH 5 FS 0.3 dexamethasone, 0.2 mg/kg given orally every 24 hours 17 DSH 3 MC 1.5 (cases 5, 7, 8, 13, 15, 18, 19, 21, 25, 26). None of the 18 DLH 1 FS 0.2 cats were reported to be anxious and none had identified 19 DSH 2 FS 1.0 environmental stressors that might have provoked 20 DSH 4 FS 0.5 behavior-induced skin disease. 21 DSH 7 FS 2.0 All cats were free of bacterial and fungal , 22 DSH 9 FS “years”o o and parasites based on physical examination and 23 DSH 9 FS “years” appropriate laboratory investigations. Skin biopsies were 24 DSH 2 MC 1.0 not performed. Twenty-one cats (cases 1–12, 15–17, 19– 25 DSH 6 FS 1.5 23, 26) failed to improve while being fed an appropriate 26 DSH 5 FS 0.2 27 DSH 4 MC 0.4 home-cooked or commercial novel protein diet for 4 to 6 weeks6, 12). In six cats (cases 13, 14, 18, 24, 25, 27), *Cases 1–12, 15–17, 19–23, and 26 had atopic dermatitis. a strict novel protein diet was impossible. Thus, these Cases 13, 14, 18, 24, 25, and 27 had atopic dermatitis and/ six cats may have had atopic dermatitis, food allergy, or or food allergy. †DSH = domestic shorthair. DLH = domestic o both. Excessive scratching, licking, chewing, grooming, longhair. ‡FS = spayed female. MC = castrated male. In or combinations of these were obvious to the owners of these cats, the owners were not sure how long disease had been present, and could only say for “years”. all cats prior to the initiation of the loratadine trial. Each cat was treated with loratadine (Loratadine Tablets; Perrigo, Allergan, Michigan 49010, USA), 5 mg (hence, cats received from 0.9 to 1.6 mg/kg) by mouth additional 30-day period in order to document repeatable every 24 hours7, a) for 2 weeks. A 2-week treatment and sustainable response1, 5, 9). period was selected based on observations made in other studies in which antihistamines were given to pruritic Results cats1, 5, 9). Clients were asked to evaluate reduction in pruritus as nonexistent, mild (<25% reduction), moderate All 27 cats completed the study. There was a marked, (25% to 50% reduction), or marked (>50% reduction). If reproducible reduction in pruritus in only one cat (case there was a reduction in pruritus after the initial 2-week 26). For the other 26 cats, reduction of pruritus was trial, the loratadine was to be discontinued. If pruritus nonexistent. No adverse side effects were observed returned, the loratadine was to be re-administered for an during the trial. Scott D.W., et al. 9

Discussion References

Antihistamines have been reported to satisfactorily 1) Griffin, J.S., Scott, D.W., Miller, W.H. Jr. and reduce pruritus in allergic cats in a variable percentage Tranchina, M.M. 2012. An open clinical trial on of the animals treated1, 4, 5, 9). In one large retrospective the efficacy of hydrochloride for the study11), antihistamines were reported to control the management of allergic pruritus in cats. Can. Vet. J. pruritus in 30.6% (34 of 111 cats) of the cats with atopic 53: 47–50. dermatitis. In that study, control was maintained for 2) Marzanatti, M., Monopoli, A., Trampus, M. and follow-up periods of 0.5 to 9 years, and for >1 year in Ongini, E. 1989. Effects of nonsedating 28/34 (82.4%) cats. Adverse side effects were rarely H1-antagonists on EEG activity and behavior in the reported. cat. Pharmacol. Biochem. Behav. 32: 861–866. In contrast to the anecdotal benefits of loratadine in 3) McEvoy, G.K. 2012. pp. 39–44. In: AHFS Drug the management of allergic cats espoused in textbook7) Info 2012. American Society of Health-System and on the worldwide weba), only one cat (4%) in our Pharmacists, Bethesda. open clinical trial had a reduction in pruritus. A prior 4) Miller, W.H. Jr. and Scott, D.W. 1990. Efficacy double-blinded, placebo-controlled study revealed that of chlorpheniramine maleate for management of loratadine (1 mg/kg given orally every 24 hours) was pruritus in cats. J. Am. Vet. Med. Assoc. 197: 67–70. also ineffective in dogs with allergic pruritus8). In our 5) Miller, W.H. Jr. and Scott, D.W. 1994. Clemastine loratadine study, no side effects were observed, which fumarate as an antipruritic agent in pruritic cats: is consistent with anecdotal informationa). In addition, results of an open clinical trial. Can. Vet. J. 35: loratadine had previously been administered to normal 502–504. cats (3–30 mg/kg, given orally once) with no disturbance 6) Miller, W.H. Jr., Griffin, C.E. and Campbell, K.L. of sleep patterns or behavior2). Perhaps larger doses 2013. pp. 388–392. In: Muller & Kirk’s Small th of loratadine would be more effective in reducing the Animal Dermatology, 7 ed. Elsevier-Mosby, St. pruritus of allergic cats. Louis. In conclusion, under the conditions of this study, 7) Mueller, R.S. and Jackson, H. 2003. pp. 125–136. loratadine (5 mg/cat, every 24 hours) was found to be Atopy and adverse food reaction. In: Foster, A.P. effective as an antipruritic agent in only 1 of 27 cats (4%) and Foil, C.S. (eds.). BSAVA Manual of Small nd with allergic skin disease. Animal Dermatology, 2 ed. British Small Animal Veterinary Association, Gloucester. Footnote 8) Paradis, M. 1996. Nonsteroidal antipruritic drugs in dogs and cats: an update. Bull. Can. Acad. Vet. a)The following websites containing anecdotal Dermatol. 12: 3–7. information on the use of loratadine in allergic cats were 9) Scott, D.W., Rothstein, E., Beningo, K.E. and visited on September 17, 2014: Miller, W.H. Jr. 1998. Observations on the use of www.veterinarypartner.com/Content,plx?P=A&A=2114 cyproheptadine hydrochloride as an antipruritic www.justanswer.com/cat-health/2dld5-give-cat- agent in allergic cats. Can. Vet. J. 39: 634–637. loratadine-types-antihistam.html 10) Scott, D.W., Miller, W.H. Jr. and Erb, H.N. 2012. www.ehow.com/facts_5673392_loratadine-dosage- Feline dermatology at Cornell University: 1,407 cats.html cases (1988–2003). J. Feline Med. Surg. 15: 307– www.vetinfo.com/loratadine-for-cats.html 316. 11) Scott, D.W. and Miller, W.H. Jr. 2013. Feline atopic dermatitis: a retrospective study of 194 cases (1988–2003). Jpn. J. Vet. Dermatol. 19: 135–147. 12) Scott, D.W. and Miller, W.H. Jr. 2013. Cutaneous food allergy in cats: a retrospective study of 48 cases (1988–2003). Jpn. J. Vet. Dermatol. 19: 203– 210.